Speed-varying mechanism.



No. 845,896. 'PATENTED MAR. 5, 1907.

G. T. RENNERPELT.

SPEED VARYING MECHANISM.

APPLIGATTON FILED JUNE 8. 1905.

2 SHEETSSHEET 1.

5.5. Witnesses: fllventor %@Mww.$w v 9 n1 t r y was unmet: PL 'rRs co WASHINGTON, D- a No .845,896. I I-VPATENTED MAR.5,1907.

G. T. RENNERFELT. SPEED VARYING MECHANISM".

APPLICATION FILED JUNE 8. 1905.

2 SHEETS- SHEET 2.

1 l f Li 1 Li Wow W- Witnsses: v Inventor v Attorney UNITED STATES PATENT OFFICE.

GUSTAF TURE RENNERFELT, OF SORANTON, PENNSYLVANIA, ASSIGNOR TO WALTER I-I. FOSTER, OF NEWV YORK, N. Y.

SPEED-VARYING MECHANISM.

Specification of Letters Patent.

Patented March 5, 1907.

Application filed June 8,1905. Serial No. 264,241.

- in Speed-Varying Mechanism, of which the following is a specificaton.

In many machinessuch, for instance, as metal-working lathesaw1de range of speeds varying in a constant ratio is highly desirable, and a given speed should maintain itself with substantial constancy regardless of the resistance offered by the work being done. In the driving of such machines by means of an electric motor if the motor have a wide range of speed variations there is necessarily involved a special motor of lowspeed type and consequent low efficiency,

costly, heavy, and so bulky as to preclude satisfactory installation in self-contained machines.

By means of my invention I am able-to employ motors of standard type, small, comparatively low-priced, and with very limited range of speed variations, at the same time securing any desired range of speed variations in the driven machine, the speeds increasing in geometrical progression. I employ an electric motor of any ordinary type, its speed being varied within narrow limits, preferably by varying the strength of the field. I also provide for a very convenient command of all of the speeds involved in the system.

My invention will be readily understood from the following description, taken in connection with the accompanying drawings, in Which-- Figure 1 is a front elevation, part vertical section, of a speed-varying mechanism exemplifying my invention as embodied in a lathe;

Fig. 2, a side elevation of the magnet, &c.,

6, a vertical section, in a plane at right angles to its axis, of one of the clutching members pertaining to the shifting-clutch.

In the drawings, 1 indicates a frame for the support of the moving parts, the example considering it as the head-stock of a lathe; 2, the spindle of the lathe, representing the part to be driven at selective speeds; 3, an electric motor of any ordinary type; 4, the armatureshaft; 5, one member of a magnetic clutch fixed on the armature-shaft; 6, the other member of this clutch, loose on the armatureshaft; 7, this magnetic clutch considered as a whole, its details of construction being apparent from Fig. 3, this clutch being hereinafter spoken of as the slow clutch; 8, a pinion loose on the motor shaft and fast with the member 6 of the slow clutch, the construction being manifestly such that the energizing of the clutch results in looking the pinion to the armature-shaft; 9, a second magnetic clutch on the armature-shaft, this second clutch beinghereinafter spoken of as the fast clutch; 10, a pinion loose on the armatureshaft and locked thereto by the fast clutch when the latter is energized; 11, brushes for conveying current to the slow clutch; 12, brushes for conveying current to the fast clutch; 13, a counter-shaft; 14, a gear fast on the counter-shaft and engaging pinion 8 15, a gear fast on the counter-shaft and engaging pinion 10; 16, a sprocket-wheel loose on the spindle 2, this sprocket-wheel being illustrated as being incorporated with the usual cone-pulley on a lathe-spindle, the example serving to illustrate a method of machine conversion from belt drive to motor drive; 17, a sprocket-wheel fast on the counter-shaft; 18, a chain engaging the two sprocket-wheels; 19, a spur-gear loose on spindle 2; 20, a disk loose on the hub of gear 19 and carrying facial clutch-teeth; 20", a clutch-disk like clutchdisk 20, mounted loosely on the hub of sprocket-Wheel 16; 21, a shifting-clutch splined upon the spindle 2 between the two clutch-disks and adapted to engage the latter alternatively; 22, a volute spring disposed within each of the clutch-disks, one end of this spring being secured to the clutch-disk and the other to the hub on which the clutchdisk is mounted, the arrangement being such 27, a sleeve splined on the back gear-shaft and having a short exterior thread; 28, a lever engagii'ig sleeve 27 and the sliding clutch 21 in such manner that the endwise movement of the sleeve serves in shifting the clutch; 29, a spring upon the back gear-sh aft, urging the sleeve in such direction that the sliding clutch 21 will be normally engaged with clutch-disk 2O 30, an electromagnet; 31, its armature-lever carrying a tooth adapted when the magnet is energized to engage the tlnead of sleeve 27; 32, a spring serving when the magnet is inert to pull the armaturelever to position of release and disengage its tooth from the thread of the sleeve; 33, a stop to limit the releasing movement of the arm ature-lever 34, an electric controller of rotary type; 35, its contactlates; 36, the handle for adjusting the controller; 37, contact-lingers to cooperate with the controllei'plates, various electrical connections going to these contact-fingers, the mains for the supply of current to be connected with the lingers marked, respectively, with the plus and minus signs, 88, the motor held; 39 starting resistances for the armature-eircuit; 40, resistances in the field-circuit; 41 to 54, inclusive, lines indicating the points of contact of the fingers with the controller-plates as the latter are adjusted to various positions; 55, the diagrammatic line of Zero speed of the spindle 2 56, a curve illustrating the several speeds of the spindle; 57, an indication of the lowest normal speed of the spindle, and 58 an indication of the highest speed of the spindle.

The sliding clutch 21, being a jaw or toothed clutch, may not with advantage be thrown into engagement with a positively-moving clutch-disk. The introduction of springs 22 between the toothed clutch-disks and the parts driving them avoids the objection to a positive connection. The clutch 21 may, if desired, be thrown by hand in the usual manner of such clutches but it in ay be preferred to throwthe clutch by the action of the ma chine itself. Assuming sprocket-wheel 16 to be running continuously, the hack gearshaft, and consequently the spur-gear 19, will be turning continuously. Normally sleeve 27 is to the left, held there by spring 29, and the sliding clutch looks the sprocket-wheel 16 to the spindle. If the sleeve be shifted to the right it will obviously eilect the unlocking of the sprocket-wheel from the spindle and bring about the locking of spur-gear 19 to the spindle, the spindle then being driven at a much lower rate of speed than the sprocketwheel. Normally the tooth of the armaturelever 31 is free of the thread of sleeve 27. If magnet 30 be energized, then the tooth. of its lever engages the thread of the sleeve and acts as a stationary nut, whereupon the sleeve shifts to the right and throws the sliding clutch to spur-gear 19. W hen the throwing movement shall have been completed,

eeasee the end of the thread upon the sleeve is reached and the tooti'i is at liberty to descend somewhat further and engage behind a shoulder upon the sleeve, and thus lock the sliding clutch into engagement witn the spurwheel independent of the thread upon the sleeve. When the magnet is deenergized. then spring 32 withdraws the teeth of the armature-lever from the sleeve and the spring throws the clutch out of engagement with spur-gear 19 and into engagei'nent with the clutch-disk carried by the sprocket-wheel l (3. With the sliding clutch to the left and the spindle consequently running at the speed of sprocket-wheel 16, the condition is that of back gear out, while with the sliding clutch. to the right, locking spur-gear 12) to the spindle, the condition is that of back gear in. Any convenient switching device might be employed for bringing about the desired action of magnet 30; but the illustration provides for bringing that magnet within the domination of the (jOilll'OllM' which dominates the other circuit condi tions.

As regards the inotor-clutches 7 7 and 0, it needs here only to be said that when the clutches are deenergized their piniens are free on the armature-shaft, but when respectively energized they serve in looking their pinions to the arm attire-shaft.

The controller, as illustrated in Fig. l, comprehends two controller-plates arranged in cylindrical form and provided with a handle for turning the cylindrical structure. in Fig. 5 the plates are illustrated. diagrami'natically and the movement of the plates to the right is progressively from the idle condition of the motor to the condition of highest speed for the spindle.

In Fig. 5 the speed ordinates of the diagram have been prolonged downwardly over the controller-plates to indicate lines of contact for the controller-lingers as the plates are adjusted, and these lines may therefore be spoken of as speed-lines for the spindle or as position-lines :for contact-lingers. In Fig. 5 the controller-plates are free from the fingers and everything is idle. By annlyzing Fig. 5 and assuming the controllerplates, which never change their relationship to each other, to be moved to bring the lines 41 to 54, inclusive, successively under the contact-fingers it will be apprehended that when position-line 41 is under the contact fingers the motor will start with full strength of field and with both sections of the resistance 39 in series with its arm atures, the slow clutch is at the same time put into action, due to the energizing of winding 8, and the back gear is thrown in, due to energizing of magnet 30. It will he seen from the diagram that as the controller-plates are further moved to the right the first section, the large one, of

the starting resistance is short-circuited at to its second speed, and then at 54 to its 42 and the second section is short-circuited at 43, so that the speed is gradually increased i from line 41 to line 43. It will further be seen from the diagram that the fast clutch 9 i will come into action instead of the slow, clutch 8 on the line 46. At the line 49 the slow clutch is again in action, ,the fast clutch is out, and the back gear is out, this latter fact being due to the deenergizing of magnet 30, and it will further be seen that at line 52 the slow clutch is out and the fast clutch is in, the back gear remaining out from 49 to 54. The first two speeds at 41 and 42 with resistance in the armature-cir cuit will ordinarily not be used as actual wprking speeds of the machine, so that the speed at 43 is to be considered as the first working speed with the motor at its lowest normal speed and the transmission to the spindle at highest ratio of reduction, thus giving to the spindle its first normal speed or the lowest speed of the system. The next step 44 introduces one of the resistances into the shunt-field and gives to the motor its second speed and t0 the spindle its second speed. The next step introduces the other of the resistances 40 into the shunt-field and gives to the motor its third speed and to the spindle its third speed, this condition corre sponding with line 45 on the diagram. It will be further seen that the next step 46 restores the motor to its first speed, but substitutes the-fast clutch for the slow one, that the successive steps bringin first the second, then the third speed of the motor, that the motor is then, at 49, put again to its first speed with the back gear out and the slow clutch in, then the motor goes to its second speed at 50 and then at 51 to its third speed, that then the motor goes again at 52 to the first speed with the slow clutch out and the fast clutch in, that the motor then at 53 goes third speed. The three motor speeds have thus been made to result in the twelve spindle speeds. The geometrical progression of the increase in the speeds is due to the proportioning of the motor speeds and of the gear ratios. Let the resistances for varying the motor speeds be such that the spindle speed resulting from the third motor speed bears the same ratio to the second spindle speed that the second spindle speed bears to the first spindle speed. The ratiois to be constant for any two neighboring spindle speeds in the system, and this constant may be represented by 1c. The spindl speed resulting from the substitution of the fast clutch for the slow clutch is to bring about a ratio of increase represented by the constant 7c 1 and similarly as to other modifying-gear-as, for instance, the ratio ofincrease effected by the back gear. Having selected maximum and minimum speeds for the spindle and determined upon the number of speeds desired,

the desired geometrical relationship can be arrived at without trouble and with accuracy, any slight departures from absolute accuracy as incident to the exigencies of tooth-numbers being generally inconsiderable. It is to i be observed that there is a group of motor speeds of comparatively narrow range and that this group is employed repetitively, the slowest speed of the motor producing upon the spindle a higher speed than was last produced by the highest speed of the motor.

The following general rule can be formulated: If the spindle is to run at n number of speeds varying in geometric progression from minimum 8 to maximum S, then the constant 7c, which equals represents the ratio between any two contiguous speeds, and the ratios of the gears as well as the variations in the speed of the motor itself are certain powers of said constant. If the number of motor speeds is m, then the extent of the speed variation in the motor is equal to 7c and the ratio of the first gearing is equal to if, and the ratio of the second gearing is 7c, and the ratio of the third gearing is la if a third gearing be employed. More than three would seldom be required. Applying values to the illustrated exam ple, assume them as follows: highest spindle speed S=380; lowest spindle speed, 8 27; n=twelve speeds of the spindle, to vary in geometric progression; m three speeds of the motor, and lowest speed of motor 1050 r. p. m. The formula gives for this case motor willbe 1.27 X1050 1330 r. p. m. The ratio of the gearing will be ,3 WA I Z 1. 27 2.06.

and the ratio of the back gear will be The exact values of the second and third motor speeds are obtained by choosing the proper values for the resistance in the field winding of the motor. The ratios of the gearings are obtained by making the gears of six teeth, gear 14-. to have one l'iunerez'i and twelve teeth, pinion 10 to have l'o;t ,*'four teeth, gear 15 to have ninety-tour teeth, sprocket-wheel 17 to have twentysix to th, sprocket-wheel 16 to have for y-six teeth, pinion 24: to have fiftydive teeth, gear 25 to have eighty-nine teeth, pinion 26 to have thirty teeth, gear 19 to hiive seventyeight teeth. These gears will give a ratio between the fast and the slow clutch-gearing of O seize-4 .2 26 24L .2. 1%

which is fairly close to the desired figure, 2.06. The number of teeth In the wheels constituting the heck gear will settle its ratio to which is close enough to the desiredv 4.23.

The train 17 and 16 serves only 01 transmit ting the motion and for reducing but not for vin'yii'ig the speed.

*i-om the example end formula given it is manifest that the system is capable of lending itself to a wide range of well-pinpoitioned spindle speeds founded on any plurality of motor speeds. The details of construction are not at all to be viewed limitations, but merely as exemplifications ol' the invention.

I claim as my invention- 1. In s eedva';*ying HICCllZtDlSID, the combination of an electric motor, a spini'lle to he driven at selective rates of speed, an intermediate transmission device, a direct connection between said intermediate tiansinission device and said spindle, a controller serving to give the motor a plurality of speeds, a first transmitting device connecting said motor and said intermediate transmission device, a second. transmitting device for connecting said motor with said intermediste trensmission device at a difl'erent speed ratio "om the first, the relative speed ratios of Sitll transmitting devices being such as to give a progression in spindle speeds of a value approxiinete to a geometriciitl ratio, and means actuated by said controller for bringing said trans-- mitting devices into action alternatively.

2. In speed-varying mechanism, the comhination of an electromotor, a spii tile to he driven thereby at selective speeds, a EllLtlil intermediate the motor and the spindle, a plurality of gear-trains for transmitting motion from the motor to the shaft, a connection -from said shaft to LlL'l spindle for impelling the latter at a determined relative retio of speed, clutches in the gear-trains for rendering said trains alternatively active, it controller, and connections between. the controller end the motm" end the clutches.

In speed-varying i'neclmnisn'i, the comhinatioi'i of an GlGOlJJJOmOtOT, spindle to he driven thereby at selective speeds, a shil't ii'itermediatc the motor and the spindle, a 'ilutality of gees-trains for transmitting motion fioni the motor to the shelt, a connection from said sh t to said spindle for impelling the l" ter tit a (lQiLOlllllllOil relative ratio of speei, another connection from said sl' it to said spindle for impelling the hitter at a lower relative speed ratio, means controlled by an electromagi'iet for rendezing either of said. connections el'leotive, clutches -trains for rendering said trains alteznatively active, a controll r, and connections between the coi'itroller and he n1otot, clutches and the electromegnct.

l. In speed-va ying .lHtCllitJllSlll, the combination, suhstitntiitlly as set 'Foith, of a spindle, a driving device therefor, a train for transmitting motion 'flfOIl'l the driving device to the spindle, a clutch in said ll'iitlll, n1echsnism connected with the spindle for moving the clutch, an electromsgnet, means for coin trolling the magnet, and conimcthms hetween said mechanism and the imstnLe ol' the magnet for throwing said meclnmism into action 5. ln speed-varying mechanisn'i, the comhinetion, suhstantislly as set forth, oi a spindle, a driving (levice therefor, a tzain l'oi trin'ismitting motion from the d. iving device to the spindle, a clutch in said train, a 6011:. y sliding memhe? turi'iing with the spindle and connected with said clutch and having an eXti ior th: l, an clectromagnet, means for coiitfolling the magi'iet, a discngigethle nut element to. said thread, and a connection hetween s iid. nut ClGl'l'lOl'lll end the armntu; e of the magnet.

6. In speedvarying IHCGllZtlllSl'll, the coml instion, suhstanially as set forth, oi an electric motor, it spindle to be driven the. eh at selective speeds, a plurality of pinions loose on the annatlire-shaft of the motor, diverse-ratio ge trains connecting the pinions with the spii'idle, a magnetic clutch it each pinion for locking the pinions alternatively to the a; m atu? i-shsilit, and means For electrical l y cont'.' lling said motor and clutches.

7. In. speed-v rying meclm-nis-nn, the comhinctioi'i, initially as set forth, of a spindle, driving means theqelor, a tiu'tnsmittingtrain coimecting the driving means with the spindle, it tooth-clutch interp sed in sgiid train, means for thiiowing the clutch while one of its memhe; s is in motion, and a sp1 ing interposed in the t1'='in at the clutch to receive the drivingstrain as the clutch is thrown.

8. In. speed-varying mechanism, the eomhination, sul stintially as set forth, of a spin die, an electric motor for driving the same, :1 plurality of diverse-ratio gear-trains connecting the spindle with the motor, magnetic clutches in said trains, toothed clutches in said trains, power-transmitting springs in the trains at the toothed clutches, and means for controlling the clutches.

9. The combination of an electric motor, a gear loose on each end of the motor-armature shaft, means for connecting said gears with said shaft selectively, a counter-shaft, two gears thereon, each engaging one of the gears first mentioned, a spindle, a driven member driven from said counter-shaft, means for connecting said driven member directly with said spindle, and reductiongearing intermediate said member and said spindle.

10. The combination of an electric motor, a gear loose on each end of the motor-armature shaft, means for connecting said gears with said shaft selectively, a counter-shaft,

two gears thereon, each engaging one of the gears first mentioned, a spindle, a driven member driven from said counter-shaft, means for connecting said driven member directly with said spindle, reduction-gearing intermediate said member and said spindle, and magnetically-controlled means for connecting said driven member and said spindle v through said reduction-gearing.

11. The combination of the motor, the plurality of primary gear ratios, the spindle, the direct-drive connection from the primary gearing to the spindle, and the m agneticallycontrolled reduction-gearing, substantially as described.

GUSTAF TUBE RENNERFELT.

Witnesses:

MARY C. KIESEL, CHARLES A. KIESEL. 

